1. Field of the Invention
The present invention relates to an oil cooler that is contained in a radiator tank and used for a motor vehicle or the like.
2. Description of the Related Art
A conventional oil cooler contained in a radiator tank is disclosed in Japanese patents laying-open publication No. 2001-272195, No. 2002-195783, and No. (Tokkaihei) 11-211378, and Japanese Patent No. 3245739. The oil cooler is provided with a heat exchange part for cooling oil flowing therethrough, two connecting pipes each for connecting a top portion of a communicating passage of the heat exchange part and a vehicle-side device, and two patch plates each for fluidically plugging a bottom portion of the communicating passage.
The heat exchange part includes a plurality of elements, each of which has coupled shell members containing an inner fin and are piled up. The two communicating passages are formed vertically at the both side portions of the elements so as to fluidically communicate interior portions of the elements with each other.
The top portions of the communicating passages are fluidically connected with the connecting pipes, respectively, by using a cylindrical pipe connector which is inserted into a pipe connecting hole formed on the radiator tank. In general, the connecting pipes are screwed together with the pipe connecters with a seal member arranged therebetween.
This conventional oil cooler, however, encounters the following problems in production management, causing high manufacturing costs and others. Specifically, it takes some trouble with tightening torque management when screwing a nut to the pipe connecter to fix the connecting pipe, and seal-member extrusion-or-intrusion preventing management. In addition, various diameter types of pipe connectors are required so as to fit different diameters of the connecting pipes, which increases its design and manufacturing costs. Further, the heat exchange part and the radiator tank are fixed with each other by using an additional member, which also increases the number of parts and increases the manufacturing costs because of necessity for high accurate temporary assembly of the pipe connectors, the heat exchange part, and the radiator tank in order to avoid bad brazing and oil leak.
On the other hand, the bottom portions of the communicating passages are plugged by using the patch plates. FIGS. 20 and 21 show different conventional examples using the patch plates.
Referring to FIG. 20, an oil cooler is fixed at its top portion with a connecting pipe 02, and provided with a plurality of elements 05 and 05b, in which the undermost element 05b has the same construction as those of the other elements 05. In order to fluidically plug a communicating passage RO, a patch plate 013 is fixed by brazing to a lower shell member 07 of the undermost element 05b with a seat member S arranged therebetween.
Referring to FIG. 21, another oil cooler is fixed at its top portion with a connecting pipe 02, and provided with a plurality of elements 05 and 05b, in which the undermost element 05b has a lower shell member 07 in a shape different from those of the other elements 05; In order to fluidically plug a communicating passage RO, a patch plate 013 is fixed by brazing to the lower shell member 07 without such a seat member shown in FIG. 20.
However, the oil cooler of the former requires the seat member S in order to firmly fix the patch plate 013 to the undermost element 05b by brazing, which increases the number of parts and its manufacturing process and costs. The oil cooler of the latter requires different shaped elements, increasing the number of parts and its manufacturing process and costs.
It is, therefore, an object of the present invention to provide an oil cooler which overcomes the foregoing drawbacks and can decrease the number of parts and its manufacturing process and costs.